Anthromorphic animals are animals that walk upright, like Mickey Mouse or Pluto. The convention is held annually at the David L. Lawrence Convention Center and attracts around 5,600 people from around the world. Organizers estimate the event brings in around $7 million for the city of Pittsburgh.

Anthrocon is basically a convention of artists and fans in a unique subculture that gained popularity on the Internet. Its followers are often referred to as furries because they can be spotted wearing fur tails, animal ears or full fur suits.

"I'm not a fur suitor myself, I have friends who do it. It's an expression of their creativity. It's no different than knitting a quilt or something like that," said Mike Kisior from Cranberry.

Thursday, the FBI was looking into an Internet threat to bomb the convention center. Fans saw the initial threat spread on Facebook and aren't too concerned with it.

"Initially what I think it was was a 10-year-old who couldn't come to convention so he got a little mad, got a little upset, and just went on a little crying rant," said Joe "cage" Vullo from Buffalo, New York. "I'm not worried about it. It's the same thing as any terrorist threat, which is what people want to call it. That's fine."

Anthrocon runs through Sunday.

Photos: Furries in Pittsburgh

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Anthrocon Convention

Thousands of people from across the U.S. come to Pittsburgh for Anthrocon, the world's largest furry convention. It has been held Downtown since 2006.

WELL, YOU KNOW THE FURRIES ARE BACK IN PITTSBURGH. GIANT ANIMAL COSTUMES GETTING LOTS OF ATTENTION IN OUR CITY, AND EVEN AN ONLINE THREAT CANNOT PUT A DAMPER ON THE EXCITEMENT OUT THERE. WHILE THE FBI INVESTIGATES TONIGHT, IT'S BUSINESS AS USUAL AT ANTHROCON. ASHLIE HARDWAY IS LIVE AT THE CONVENTION WITH THE ANSWER TO THE QUESTION MANY OF YOU ARE ASKING. WHAT ARE THEY DOING HERE? Reporter: WELL, WENDY AND MIKE, I CAN EXPLAIN THAT FOR YOU. I AM HERE WITH MY FRIEND LUCAS. HE IS A SILVER FOX. YOU MIGHT SEE MANY PEOPLE DRESSED LIKE HIM WALKING AROUND THE DOWNTOWN AREA. HE'S ALL THE WAY UP FROM SOUTH CAROLINA. IT'S HIS FIRST TIME IN PITTSBURGH. AND YOU KNOW, ORGANIZERS OF THIS EVENT, ANTHROCON, EXPECT NEARLY 6,000 PEOPLE JUST LIKE LUCAS WILL BE HERE IN OUR CITY THIS WEEKEND. ACTUALLY THEY BRING MORE THAN JUST COSTUMES TO TOWN. THEY'RE BACK. THE FURRIES HAVE OFFICIALLY LANDED IN THE' BURGH. I LOVE THIS CITY. Reporter: AND PITTSBURGH SEEMS TO WELCOME THEM WITH OPEN ARMS. THANK YOU. IT'S INTERESTING, I LIKE IT. THEY BRING A LOT OF MONEY INTO THE CITY SO I THINK IT'S A GOOD THING. Reporter: $7 MILLION TO BE EXACT ACCORDING TO ORGANIZERS. ABOUT 5600 FURRIES WILL TAKE PART IN ANTHROCON THIS WEEKEND, BUT WHAT IS IT? IT'S A LOT OF FANTASY, SCI-FI, STUFF LIKE THAT. Reporter: IT'S BASICALLY A CONVENTION THAT CELEBRATES ANIMALS THAT WALK UPRIGHT FANDOM. WE GET TOGETHER AND SHARE CREATIVE IDEAS. SOME JUST DRAW ART AND WE JUST HAVE A GOOD TIME. Reporter: WHAT ABOUT THOSE TAILS IN FUR SUITS? I'M NOT A FUR SUITOR MYSELF. I HAVE A FEW FRIENDS WHO DO IT. IT'S AN EXPRESSION OF THEIR CREATIVITY. IT'S NO DIFFERENT THAN KNITTING A QUILT OR SOMETHING LIKE THAT. Reporter: THIS IS A SECURITY FURRY WHO ROLLER BLADES AROUND IN JULY IN A FUR SUIT MAKING SURE THE ANIMALS MIND THEIR MANNERS. YES, THE SUIT IS VERY HOT TO BEGIN WITH. FORTUNATELY WE HAVE A RELATIVELY COOLER DAY, THERE'S A LITTLE BIT OF A BREEZE. WHEN I'M ROLLING, THERE'S SOME BREEZE SO I GET A LOT OF AIR FLOW FLOWING THROUGH THE SUIT AND THAT HELPS ME COOL DOWN.